Thermodynamics Set 12

Mechanical Engineering

Practice Mode Previous Next
On This Page

This set of Thermodynamics Multiple Choice Questions & Answers (MCQs) focuses on Thermodynamics Set 12

Q1 | The perfect heat engine works on the Carnot cycle between 1000?C and 200?C. The efficiency of the engine will be
  • 60%
  • 68.20%
  • 37.20%
  • 80%
  • 62.80%
Answer: 62.80%
Q2 | Joule Thomson coefficient for an ideal gas having equation pv = RT is
  • Zero
  • 0.5
  • ?100?C
  • Unity
Answer: Zero
Q3 | The efficiency of a dicsel cycle will be maximum when
  • Engine is super-charged
  • Cylinder is water cooled
  • Injection pressure is high
  • Cut off is zero
  • Speed is high
Answer: Cut off is zero
Q4 | Thermodynamic equilibrium is completely defined by the specifications of
  • Internal energy
  • Generalized displacement
  • All the above together
  • None of the above
  • It is dimensionless
Answer: None of the above
Q5 | In the polytropic process equation pvn Constant, if n = 0 the process is termed as
  • Constant volume
  • Constant pressure
  • Isothermal
  • Constant temperature
  • Adiabatic
Answer: Constant pressure
Q6 | Out of the following materials which may be expected to have higher value of thermal conductivity?
  • Asbestos
  • Refractory brick
  • Wood
  • Clay
  • Nichrome
Answer: Nichrome
Q7 | In a Carnot engine, when the working substance gives heat to the sink
  • Changes depend on the operating conditions
  • The temperature of the sink increases
  • The temperature of both the sink and the source decreases
  • The temperature of the sink remains the same
  • The temperature of the source decreases
Answer: The temperature of the sink remains the same
Q8 | Which of the following is not a property of the system?
  • Temperature
  • Pressure
  • Specific volume
  • Work
  • None of the above
Answer: Work
Q9 | Which of the engine is used for fighter bombers?
  • Pulsejet
  • Ramjet
  • Turbo prop
  • Rockets
  • Turbojet
Answer: Turbojet
Q10 | A gas can never be liquid
  • Above critical temperature
  • When it is diatomic
  • When it is impure
  • When it is reactive with any other gas
  • Above room temperature
Answer: Above critical temperature
Q11 | A mixture of liquid and vapour Freon in a vessel is an example of
  • Isolated system
  • Heterogeneous system
  • Open system
  • Closed system
  • Transient system
Answer: Heterogeneous system
Q12 | Heat exchanger used in a steam condenser of a thermal power plant is
  • Direct contact type
  • Recuperator type
  • Regenerator type
  • Any one of the above
  • None of the above
Answer: Recuperator type
Q13 | A piece of paper wrapped tightly on a copper rod will get charred relatively slowly when held over a flame as compared to a piece of paper wrapped tightly on any of the following rod except
  • silver rod
  • iron rod
  • Pulsejet
  • brass rod
  • wooden rod
Answer: silver rod
Q14 | Three engines A, B and C operating on Carnot cycle use working substances as oxygen, hydrogen and air. Which engine will have higher efficiency?
  • Engine C
  • All will have the same efficiency
  • Pulsejet
  • Engine B
  • Angine A
Answer: All will have the same efficiency
Q15 | In a diesel engine fuel is injected
  • after the end of compression stroke
  • at the beginning of compression stroke
  • at the end of compression stroke
  • before the end of compression stroke
  • Pulsejet
Answer: before the end of compression stroke
Q16 | The molecular volume of all the gases at 2 ata and 30?C is
  • 12.847 cu-m
  • 1.562 cu-m
  • 25.794 cu-m
  • 8.48 cu-m
  • 1.0 cm-m
Answer: 12.847 cu-m
Q17 | Other factors remaining constant, if the temperature of source is increased, the efficiency of Carnot engine will
  • will not change
  • decrease
  • Pulsejet
  • increase or decrease depending upon temperature ratio
  • increase
Answer: increase
Q18 | The sequence of processes that eventually returns the working substance to its original state is known as
  • Thermodynamic cycle
  • Process
  • Zeroth law of thermodynamics
  • Event
  • Thermodynamic property
Answer: Thermodynamic cycle
Q19 | Which of the following is not a path function?
  • Work
  • Heat
  • Kinetic energy
  • Thermal conductivity
  • All of the above
Answer: Thermal conductivity
Q20 | In axial flow compressors, the phenomenon of stalling of blades occurs when
  • Air stream is not able to follow the blade contour
  • Blades vibrate violently
  • Air stream flows with sonic velocity
  • Air stream blocks the passage
  • Blades fail due to creep
Answer: Air stream is not able to follow the blade contour
Q21 | COP of the engine is
  • 5.33
  • 4.33
  • 3.33
  • 2.33
  • Pulsejet
Answer: 4.33
Q22 | A diathermic wall permits
  • Radiation heat flow only
  • Conduction heat flow only
  • No heat exchange
  • Heat exchange by all the three modes of heat transfer
  • Convective heat flow only
Answer: Heat exchange by all the three modes of heat transfer
Q23 | Which of the following is not a reversible cycle?
  • Carnot cycle
  • Stirling cycle
  • Ericsson cycle
  • Otto cycle
  • All of the above
Answer: Otto cycle
Q24 | In which case the heat transferred from the air when compressed from 1 ata 15?C to 6 ata would be maximum
  • Adiabatic
  • Polytropic pv1.35 = C
  • Polytropic pv1.3 = C
  • Polytropic pv1.31 = C
  • Isothermal
Answer: Adiabatic
Q25 | The dimensions of 'a' will be
  • Pulsejet
  • ML2T
  • ML6T-2
  • ML3T-2
  • ML5T-2
Answer: ML5T-2
Previous Next